The present invention relates to the general field of treating obesity. The invention is directed in particular toward compositions for the curative and prophylactic treatment of obesity, but it also relates to the esthetic treatment of a human being to enhance his or her figure.
The therapeutic objective as regards obesity is well defined: it is a matter either of allowing the individual to lose a significant amount of weight, or of helping the individual to maintain a weight level which is as low as desired.
Several types of approach have been envisaged to date.
Nutritional approaches are directed toward reducing the supply of energy in the form of foods. This can be achieved either by drastically reducing the energy supplies or by replacing high-energy nutrients with others which are lower in energy: such as indigestible substitute fats, structured triglycerides which are difficult to assimilate or dietary fibers which cannot be assimilated.
The therapeutic approaches may have a variety of targets.
Reducing the food intake may be the first objective. Attempts to reduce the food intake may be made by using anorexigenic substances, whose short-term effects are proven, but whose duration of use is limited on account of adverse side effects. In fact, very few of these products can truly be used and their long-term efficacy remains highly debated. New molecules are undergoing assessment or may do so in the near future, but their value still remains to be shown.
A second objective may be to increase the expenditure of energy by using thermogenic substances which act at the central or peripheral level. The use of these substances still remains limited.
A third objective is to reduce the assimilation of the dietary lipids, or optionally even that of the carbohydrates. This is a more recent approach, but is gaining in interest. A reduction in the assimilation of the dietary lipids may be obtained either by reducing the activity of the digestive enzymes concerned, or by modifying the properties of the interfaces transporting the lipid molecules, emulsions, vesicles or micelles.
The traditional use of tea is in the form of an infusion, for which the tip of the stems, comprising the last two leaves and the bud, are used. After harvesting, these leaves may be subjected to a fermentation, resulting in a transformation of the chemical substances they contain and in particular the catechols, which corresponds to black tea, or else may be dried immediately, thus giving green tea.
Besides catechols, tea contains caffeine, the diuretic effect of which is well known. This diuretic effect is the reason for the traditional use of green tea as a medicinal plant to promote the elimination of water by the kidneys, either in the case of urinary disorders or as a supplement to weight-reducing diets. The presence of caffeine is also the reason for the traditional use of tea in conditions of fatigue (asthenia).
Numerous epidemiological studies carried out on certain populations have clearly demonstrated the beneficial effects of the chronic ingestion of tea, and more particularly of green tea. Thus, the long-term consumption of green tea is thought to be anti-atherogenic on account of its hypocholesterolemiant effects (Muramatsu et al. 1986, Yang et al. 1997) and its ability to prevent the oxidation of LDLs in the circulation (Tijburg et al. 1997). Green tea is also known for its anti-mutagenic and anti-carcinogenic effects. Thus, it has been shown that green tea significantly reduces the risk of colorectal, skin and breast cancers (Blot et al. 1997, Conney et al. 1997, Dreosti et al. 1997, Jankun et al. 1997, Ji et al. 1997).
The traditional use of green tea as a diuretic is currently performed in the form of infusions, liquid extracts, extracts of plant powders or extracts in gel capsules or tablets. In these various forms, the green tea, often combined with another diuretic plant, is generally used at a dose corresponding to 1 to 3 g of plant per day.
In the context of screening pharmacological properties of various plants, it has been discovered that extracts of green tea have noteworthy properties which allow them to be used in the treatment of obesity.
The human body continually expends energy in order to function. The origins of this expenditure of energy are threefold: the metabolism, muscular work and thermogenesis, which corresponds to the energy expended by the body to maintain a constant temperature.
The expenditure of energy is compensated for by the energy supplied by the assimilation of foods. If the energy supplied from the dietary ration is strictly identical to the energy expended, the individual maintains a stable weight. If there is an excess supply of energy, the body stores this energy in the form of fats (increase in weight), and if there is a deficit in the supply of energy, the body draws the energy it lacks by burning off the fats stored (loss of weight). However, in this latter situation of an energy deficit encountered in the course of weight-reducing diets, the body reacts to save energy and reduce thermogenesis. This is the control mechanism which accounts for the failure of weigh-reducing diets. Specifically, after losing weight for a few weeks, the individual""s weight stabilizes. If they wish to continue to slim, they must further reduce their food intake.
The full value of being able continually to increase thermogenesis, in particular in the course of a low-calorie diet during which it is lowered, may thus be appreciated. Various chemical substances stimulate thermogenesis, such as nicotine, ephedrine, aspirin, caffeine, etc., but none of them has made it possible to produce a medicinal product for treating obesity since the doses required to obtain an increase in thermogenesis entail considerable side effects, which are incompatible with a treatment which is necessarily long-lasting, generally extending over several months.
This objective has been achieved in accordance with the present invention by means of a composition for the curative and prophylactic treatment of obesity, comprising an extract of green tea, Camellia sinensis, which is rich in catechols.
The present invention is also directed toward the use of an extract or powder of green tea which has anti-lipase and/or thermogenic properties, for the manufacture of a medicinal product intended for the curative and prophylactic treatment of obesity.
Finally, the present invention relates to a process for the esthetic treatment of a human being in order to enhance his or her figure, characterized in that it involves the oral administration of a catechol-enriched extract of green tea in order to bring about a loss of weight or to maintain a weight level which is as low as desired.